My invention relates to the field of automotive racing and specifically to the need to adjust the camber of a wheel of a stock car so that when the car is in a turn the rolling of the car's tires onto their sidewalls (tire roll) is reduced. However, while the invention is specifically intended for that use, it may have other uses in vehicles to provide camber where the axle structure would ordinarily permit camber.
Racing stock cars such as NASCAR'S, Grand National and Winston Cup Series cars, must use a rigid or non-independent rear drive axle system.
These stock cars operate primarily on banked oval race tracks, typically having high speed asphalt surfaces, in races that are three hundred to five hundred miles length. Races over these distances can last for several hours. On such a race track over 60% of each lap is spent with the car traveling on the banked turns of the oval race track. This means that the tires of the car are subject to a very high side load for a majority of the race. Because the cars use a rigid drive axle system considerable tire roll is experienced. Tire roll accelerates tire wear and creates unsafe handling conditions as well as actual tire failure. The rigid rear axle system required for stock car racing vehicles does not allow the wheel and the tire to remain at right angles to the banked track surface when the vehicle is in a turn; i.e. under side load conditions. Normally this problem can be corrected with a camber gain type independent rear suspension system like the ones used on the Indianapolis Speedway type racing cars. However, two reasons prevent the use of independent rear axle systems in stock cars. First, stock cars are stock American production passenger cars which do not use independent suspension systems like a camber gain type independent rear suspension system. Second and more importantly, the independent suspension units, while correcting the camber of the wheels, are not as "fail safe" as the rigid units. Thus in racing, even a car that usually has independent suspension is provided with a straight rigid axle for safety.
It is an objective of my invention to provide a very safe type of fixed cambered hub/spindle design which will provide the benefit of a cambered suspension and at the same time provide the safety benefits of a rigid suspension.
The present rear hub system incorporates a floating drive axle which is splined into a drive plate and a hub which is carried by roller bearings on a spindle which is part of the rigid axle housing. The axle housing, drive axles, bearings and hubs are on a common axis. The system is very fail safe. It prevents the axle, the brake, the wheel and the hub from falling off and causing a crash. In addition the current system is very strong and can survive the shocks and stresses associated with stock car racing much better than independent systems.
It is an objective of my present invention to improve upon the current rear hub system design used on stock cars by providing a slight camber to the hub/spindle design.
It is a further objective of the present invention to use the same types of hubs, bearings, seals, retaining nuts, and drive axles as are now being currently used by NASCAR and other racing associations. The skewed, (or cambered) spindle of the present invention thereby retains the same cross-sectional properties as the current 0.degree. of camber axles. Consequently, the safety level of the present invention is at least equal to the same level of safety that exists in the current 0.degree. camber axles.
I know of no other prior art which discloses the unique and novel design of my invention. For example, U.S. Pat. No. 4,752,079 (Fahrner) discloses a solid axle and a drive shaft connected to a wheel by a splined ball operating in a splined cavity in the wheel, with rolling balls connecting the two. A mechanism is shown to positively control the plane in which the wheel rotates by using a fluid pressure cylinder, so that not only camber but toe-in can be regulated. The only wheel bearing shown is the connection between the spherical shell of the splined cavity and a fixed block 13, having the same shape, mounted on the axle housing. (See FIG. 4 of the Fahrner patent). As is shown in figures four and five and as discussed at bottom column 4, beginning at line 47 and continuing into column 5, Fahrner contemplates either a solid axle or an independent suspension. The purpose of the invention is to increase or decrease contact between the tire and the road as required. On the other hand, the bearing arrangement is substantially different from my invention. My bearing arrangement is crucial feature of my invention and is totally different in structure. U.S. Pat. No. 3,414,290 (Wilfert) discloses wheels as being cambered but says substantially nothing about how the structure which is shown only schematically can be achieved. No structure disclosing how the wheels are cambered is illustrated. U.S. Pat. No. 4,927,169 (Scaduto) does not relate to a solid axle but to a wheel geometry in which the wheels themselves maintain zero camber while the body of the vehicle rolls. U.S. Pat. No. 3,485,506 (Nobar) shows wheels without solid axles that have a very complex independent suspension and exposed drive shafts having universal joints. U.S. Pat. No. 4,896,899 (Lawrence) shows a go-cart type vehicle having little in common with my invention except that splines are shown in the drive train.